1. Field of the Invention
This invention relates to an outboard motor steering system.
2. Description of the Related Art
In outboard motor steering systems, an add-on mechanism constituted as a separate unit from the outboard motor and used to power-assist the turning of the tiller handle is known. For example, as taught in Japanese Laid-Open Patent Application Sho 62 (1987)-125996, this mechanism typically includes an actuator such as a steering hydraulic (oil) cylinder whose driving end (piston rod head) is connected to the tiller handle through an arm or the like, and a hydraulic pump that is connected to the steering mechanism to operate in response to the angle of steering. The hydraulic cylinder is connected to the hydraulic pump by a hydraulic hose or pipe attached to the boat (hull) to be supplied with pressurized oil from the pump such that the steering of the tiller handle by human power to turn the rudder is power-assisted.
The add-on steering system constituted as a separate unit from the onboard motor has disadvantages, most notably that its structure is complicated, that it adds to the number and weight of the components, it degrades operation efficiency in fabrication or maintenance, and that it takes up space between the front of the outboard motor and the stern (rear) of the boat to fasten the hydraulic actuator and the arm, etc. In addition, the add-on steering system is disadvantageous, since the system includes many connecting parts, it tends to have an unpleasant steering “feel” owing to, for instance, plays or poor steering response in the connecting parts.